Dry electrophotographic toners comprising amphipathic copolymers having acidic functionality

Abstract

Dry electrophotographic toner compositions are provided comprising an amphipathic copolymer comprising acidic functionality covalently bonded to the amphipathic copolymer. Methods of making the toner compositions are also provided. The present toner compositions exhibit unique charge characteristics and unique chemical and charge interaction properties.

1. A dry electrophotographic toner composition, comprising:
 an amphipathic copolymer comprising one or more S material portions and one or more D material portions, wherein the amphipathic copolymer comprises at least one acidic functionality covalently bonded to the amphipathic copolymer, wherein the absolute difference between the respective Hildebrand solubility parameters of the S portion(s) of the copolymer and a liquid carrier having a Hildebrand solubility parameter of from about 13 to about 15 MPa 1/2  is less than 2.0 MPa 1/2 ; and wherein the S portion has a polydispersity of from 2.2 to 2.7. 
 
     
     
       2. The dry electrophotographic toner composition according to  claim 1 , wherein the acidic functionality is bonded to the S material portion of the amphipathic copolymer. 
     
     
       3. The dry electrophotographic toner composition according to  claim 1 , wherein the acidic functionality is bonded to the D material portion of the amphipathic copolymer. 
     
     
       4. The dry electrophotographic toner composition according to  claim 1 , wherein the acidic functionality is bonded to the S material portion and the D material portion of the amphipathic copolymer. 
     
     
       5. The dry electrophotographic toner composition according to  claim 1 , wherein acidic functionality is provided by incorporation of one or more acidic-functional polymerizable compounds in the amphipathic copolymer. 
     
     
       6. The dry electrophotographic toner composition according to  claim 5 , wherein the acidic-functional polymerizable compounds comprise greater than about 1% by weight of the total amphipathic copolymer. 
     
     
       7. The dry electrophotographic toner composition according to  claim 5 , wherein the acidic-functional polymerizable compounds comprise from about 2 to about 8% by weight of the total amphipathic copolymer. 
     
     
       8. The dry electrophotographic toner composition according to  claim 1 , wherein the acidic functionality is selected from carboxylic acids, sulfonic acids and phosphoric acids. 
     
     
       9. The dry electrophotographic toner composition according to  claim 1 , wherein the amphipathic copolymer is a (meth)acrylate graft copolymer, and the acidic functionality is provided by acidic-functional polymerizable compounds selected from the group consisting of acrylic acid, 2-acrylamido-2-methyl propane sulfonic acid, 2-carboxyethyl acrylate, crotonic acid, itaconic acid, maleic acid, methacrylic acid, pentaerythritol dimethacrylate, styrene sulfonic acid, 4-vinyl benzoic acid, and mixtures thereof. 
     
     
       10. The dry electrophotographic toner composition according to  claim 1 , wherein the S material portion of the amphipathic copolymer is prepared from polymerizable compounds comprising acidic-functional polymerizable compounds selected from the group consisting of methacrylic acid and 2-carboxyethyl acrylate. 
     
     
       11. The dry electrophotographic toner composition according to  claim 1 , wherein the S material portion of the amphipathic copolymer is prepared from polymerizable compounds comprising trimethyl cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, n-butyl acrylate, styrene, methacrylic acid and dimethyl-m-isopropenyl benzyl isocyanate. 
     
     
       12. The dry electrophotographic toner composition according to  claim 1 , wherein the D material portion of the amphipathic copolymer is prepared from polymerizable compounds comprising acidic-functional polymerizable compounds selected from the group consisting of methacrylic acid and 2-carboxyethyl acrylate. 
     
     
       13. The dry electrophotographic toner composition according to  claim 1 , wherein the D material portion of the amphipathic copolymer is prepared from polymerizable compounds comprising n-butyl acrylate, styrene and methacrylic acid. 
     
     
       14. The dry electrophotographic toner composition according to  claim 1 , wherein the composition is negatively charged. 
     
     
       15. The dry electrophotographic toner composition according to  claim 14 , wherein the composition is substantially free of charge control agent. 
     
     
       16. The dry electrophotographic toner composition according to  claim 1 , wherein the composition is negatively charged, and comprises positively charged charge control agent. 
     
     
       17. The dry electrophotographic toner composition according to  claim 1 , wherein the composition is positively charged, and comprises positively charged charge control agent. 
     
     
       18. The dry electrophotographic toner composition according to  claim 1 , wherein the composition comprises a visual enhancement additive. 
     
     
       19. The dry electrophotographic toner composition according to  claim 1 , wherein
 the absolute difference between the respective Hildebrand solubility parameters of the S portion(s) of the copolymer and a liquid carrier having a Hildebrand solability parameter of from about 13 to about 15 MPa 1/2  is less than 1.5 MPa 1/2 .